1. Field of the Invention
The present invention relates to a backlight unit, and more particularly, to a backlight unit that can be used in the illumination of a display device by adopting an LED package as a light source.
2. Description of the Related Art
Recently, various sorts of image display devices have been used and among them, a Liquid Crystal Display (LCD) may be considered to have been mainly used.
An LCD has been applied to various devices, from a thin film type wall hanging television, a notebook computer, a monitor for a desktop computer, a navigation device, a PDA, a mobile telephone to a game machine. The liquid crystals that constitute the display element of the LCD described above cannot emit light by themselves, but serve merely to transmit or block light, according to electrical signals applied thereto.
Therefore, in order to display information on a liquid crystal panel, a surface emitting device that illuminates the liquid crystal panel from the rear, that is, a backlight unit, should be separately provided in the liquid crystal display device. The backlight unit described above should uniformly emit light from the liquid crystal panel by enhancing the brightness of light and forming a uniform surface light source, such that it may be considered to be very important in terms of product quality.
As the image display device has recently become larger and slimmer with a high performance than a previous model, it can implement local dimming, with a thin thickness. Therefore, there has been active development in order to implement a backlight for providing excellent image quality in a large-sized LCD. In the case of the large-sized LCD, a brightness gradient is not uniform, as a plurality of light guide plates are disposed in parallel, in order that they are disposed so as to emit light in a single direction, thereby reducing overall brightness uniformity.
Further, clarity is lowered as bright lines or dark lines are generated, thereby causing a problem in which the thickness of the light guide plates should be increased or a special pattern should be additionally processed.
Also, several problems arise in that clarity is lowered and life span is reduced in a boundary part at the time of performing local dimming, thereby creating difficulties in development.